Accurate awareness of spatial orientation, which results from complex multidimensional interactions of sensory signals originating from multiple sources and different coordinate systems, is fundamental in maintaining posture as well as ongoing voluntary activities. Signals originating from otolith, semicircular canal, and muscle proprioceptive receptors are examples of such sensory cues required by the CNS to execute reflex control of body posture and movement. The deep cerebellar nuclei are some of the known sites of signal convergence from vestibular and proprioceptive systems. The aims of the proposed project are threefold: (1) To investigate vestibular convergence patterns in the rostral fastigial nucleus (rFN) vestibular only neurons using combinations of 3D rotations and translations (2) To investigate if some of the rFN neurons selectively encode translations and ignore changes in head orientations in relation to gravity. This project aims to quantitatively test this hypothesis using protocols with combinations of translational and tilt motion stimuli. (3) To investigate the coordinate system of encoding translational motion. Specifically, we have hypothesized that there exist rFN neurons that encode translational motion in body coordinates. Using a variety of combinations of vestibular stimulations and single unit electrophysiology, numerous relationships will be examined. The results are important in improving our understanding of the functional role of the deep cerebellar nuclei and of the significance of otolith/canal convergence in the central vestibular system.